EP0493753A2 - Verfahren zum Herstellen einer beliebig geformten Oberfläche - Google Patents

Verfahren zum Herstellen einer beliebig geformten Oberfläche Download PDF

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Publication number
EP0493753A2
EP0493753A2 EP91121875A EP91121875A EP0493753A2 EP 0493753 A2 EP0493753 A2 EP 0493753A2 EP 91121875 A EP91121875 A EP 91121875A EP 91121875 A EP91121875 A EP 91121875A EP 0493753 A2 EP0493753 A2 EP 0493753A2
Authority
EP
European Patent Office
Prior art keywords
tool
curved surface
approach
free curved
cutting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP91121875A
Other languages
English (en)
French (fr)
Other versions
EP0493753A3 (en
Inventor
Nobuo Sasaki
Tetsuzo Kuragano
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sony Corp
Original Assignee
Sony Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sony Corp filed Critical Sony Corp
Publication of EP0493753A2 publication Critical patent/EP0493753A2/de
Publication of EP0493753A3 publication Critical patent/EP0493753A3/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q15/00—Automatic control or regulation of feed movement, cutting velocity or position of tool or work
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Program-control systems
    • G05B19/02—Program-control systems electric
    • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of program data in numerical form
    • G05B19/406—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of program data in numerical form characterised by monitoring or safety
    • G05B19/4061—Avoiding collision or forbidden zones
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Program-control systems
    • G05B19/02—Program-control systems electric
    • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of program data in numerical form
    • G05B19/41—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of program data in numerical form characterised by interpolation, e.g. the computation of intermediate points between programmed end points to define the path to be followed and the rate of travel along that path
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00—Program-control systems
    • G05B2219/30—Nc systems
    • G05B2219/50—Machine tool, machine tool null till machine tool work handling
    • G05B2219/50109—Soft approach, engage, retract, escape, withdraw path for tool to workpiece

Definitions

  • the present invention relates to a free curved surface producing method, and more particularly relates to a method suitable for use in producing a free curved surface by a numerically controlled machine tool.
  • the designer in a case where the technique of CAD is used to design the geometric shape of an object having a free curved surface (geometric modeling), the designer normally specifies a plurality of points in a three-dimensional space to be passed by such a surface (hereinafter referred to as nodal points) and uses desired vector functions to allow the calculation of a boundary curvilinear network which connects the specified nodal points so as to prepare a curved surface represented by a so-called wire-frame.
  • nodal points points in a three-dimensional space to be passed by such a surface
  • wire-frame so-called wire-frame
  • the boundary curvilinear network formed by such framing process by itself represents the rough geometry of what the designer intends to design, and, if it is possible to interpolate the curved surface which may be represented by predefined vector functions using the curved lines bounding the framing spaces, the entire free curved surface (referring to one that cannot be defined by quadratic function) designed by the designer may be generated.
  • a curved surface assigned to each framing space forms a fundamental element in constituting the entire curved surface and is referred to as a patch.
  • Fig. 1 The principle of this free curved surface generating method is for example shown in Fig. 1, wherein patches to be attached to quadrilateral framing space are represented by vectors S(u,v), vector function of a third degree Bezier formula; control side vectors, vector a1, vector a2 and vector c1, vector c2 satisfying the continuity of tangential planes at the common boundary COM1 of adjoining patches, vector S(u,v)1 and vector S(u,v)2 are set on the basis of nodal points given by framing process, vector P(00), vector P(30)1, vector P(33)1, vector P(03), vector P(33)2, vector P(30)2 so that the two patches, vector S(u,v)1 and vector S(u,v)2 are smoothly connected; and, on the basis of these control side vectors, the internal control points, vector P(11)1, vector P(12)1 and vector P(11)2, vector P(12)2 are set over again.
  • the patches vector S(u,v)1 and vector S(u,v)2 may be smoothly connected consequently to their adjoining patches in accordance with the condition of continuity of tangential planes.
  • a tangential plane refers to the plane formed by the tangential vectors in the v-direction and u-direction at each point on a common boundary, and the condition of continuity of tangential planes is met when for example the tangential planes of the patches, vector S(u,v)1 and vector S(u,v)2 are the same for each point on the common boundary COM1 as shown in Fig. 1.
  • an NC (numerical control ) milling machine 1 for example of the type capable of concurrently controlled in three axial directions as shown in Fig. 2 is used so that a tool 5 such as a ball end mill adapted to be movable in the z-axis direction by a tool controlling section 4 including a motor is caused to abut against a mold 3 placed as a workpiece on an XY table 2.
  • the processing patches of the XY table 2 and the tool 5 are generated by segment height method in which they may be obtained as a tool path data through which the edge center of tool 5 is moved on an offset curved surface formed from the free curved surface data on the basis of such data as the edge radius of the tool 5.
  • a mold having free curved surface is machined by effecting control on movement in each of X-axis, Y-axis and Z-axis directions on the basis of such tool path data.
  • a method as shown in Fig. 4 may be considered in which the tool 5 is caused to approach the approach point in a predetermined circular arc.
  • an object of this invention is to provide a method for producing a free curved surface capable of achieving a tool's approach path which does not cause a damage on the processing target geometry.
  • the present invention comprises the steps of: preparing tool path data DTBM for cutting the workpiece 3 into a free curved surface contour SC specified as the processing target contour on the basis of the free curved surface data S(u,v)1, S(u,v)2 and tool information of a cutting tool 5, with respect to a cutting process region ARA where the cutting process of the processing target contour SC is effected and an approach region ARAP1 for moving the tool 5 to the cutting process region ARA; setting approach path data DTAPIN of the tool 5 so that a coincidence or approximation occurs between a processing start direction APD of the tool 5 at a cutting process starting point AP in the cutting process region ARA and the moving direction of the tool 5 when the tool 5 reaches the
  • the approach path data DATAPIN is set such that, when the tool 5 is caused to approach the point AP for starting cutting of a target contour on the workpiece 3, the moving direction of the tool 5 reaching the target contour cutting process starting point AP substantially coincide the cutting process starting direction APD of the tool 5, and the approach path data DATAPIN is then corrected, on the basis of the tool path DTBM which has been prepared correspondingly to the cutting target contour SC on the workpiece 3 so as not to cause a tool interference, so that the tool 5 does not come closer to the processing target contour SC beyond the tool path DTBM.
  • a tool interference may be avoided in the approach region ARAP1 for moving the tool 5 to the cutting start point AP and it is possible to prevent an excessive cutting on the target contour at the cutting start point AP.
  • the central processing unit (CPU) of a tool path data preparing device reads free curved surface data (i.e. data on patches, vector S(u,v)1 and vector S(u,v)2 (Fig. 2) which is previously prepared by a free curved surface preparing device, and at step SP1 as shown in Fig. 5 starts the execution of free curved surface producing program to begin the producing procedure for preparing the approach path data DTAP of the tool on the basis of such free curved surface data, vector S(u,v)1 and vector S(u,v)2.
  • free curved surface data i.e. data on patches, vector S(u,v)1 and vector S(u,v)2 (Fig. 2) which is previously prepared by a free curved surface preparing device, and at step SP1 as shown in Fig. 5 starts the execution of free curved surface producing program to begin the producing procedure for preparing the approach path data DTAP of the tool on the basis of such free curved surface data, vector S(u,v)1 and vector S(u,
  • tool path data DTBM through which the center of tool passes is prepared by the CPU for a cutting process region ARA as shown in Fig. 6 using for example the technique of segment height method on the basis of the free surface data, vector S(u,v)1 and vector S(u,v)2 (i.e. cutting target contour) and such tool information as edge shape and radius of the tool 5 (Fig. 2) to be used in the cutting process.
  • the CPU3 prepares on the basis of the cutting target contour the tool path data DTBM for a tool's approach region ARAP1 or ARAP2 to be provided at the front or back side of the cutting region ARA on the workpiece.
  • step SP4 the CPU waits until the user inputs an approach path of the tool 5 such that a substantial coincidence occurs between the moving direction of the tool 5 at an approach point AP to start cutting on the workpiece and the moving direction of the tool 5 immediately before reaching the approach point AP.
  • the user provides the approach path input data DTAPIN of a circular arc form with which the moving direction of tool at the approach point AP become the actual machining start direction APD.
  • the CPU then proceeds to the following step SP5 where, on the basis of the tool path data DTBM prepared at the above described step SP3, priority is given to the tool path data DTBM (i.e. the tool is set to move along the tool path data DTBM) when the approach path input data DTAPIN provided by the user is closer to the cutting target contour SC than the tool path data DTBM. While priority is given to approach path input data DTAPIN (i.e. the tool is set to move along the approach path input data DTAPIN) when the tool path data DTBM is closer to the cutting target contour SC than the approach path input data DTAPIN provided by the user.
  • a corrected approach path data DTAP is obtained in which the tool is moved along the tool path data DTBM for a portion in the approach section ARAP1 where a tool interference occurs on the cutting target contour if for example the tool is moved along the approach path input data DTAPIN provided by the user.
  • the tool may be moved along the approach path (DTAP) which does not cause a tool interference, since the tool path data DTBM is a data that is free from a tool interference.
  • DTAP approach path
  • the CPU moves the tool to the approach point AP on the basis of thus obtained approach path data DTAP and then moves the tool on the basis of the tool path data DTBM prepared at the above described step SP2 for the cutting process region ARA so that the workpiece is machined into the target contour SC at the cutting process region ARA, and then at step SP7 ends the free curved surface machine processing procedure.
  • the provided approach path input data DTAPIN in corrected by using a previously calculated tool path data DTBM which does not cause a tool interference, whereby a tool interference may be avoided in the approach region ARAP1 and the tool may be moved along the approach path DTAP through which an excessive cutting at the approach point AP can be prevented as much as possible.
  • the approach path input data DTAPIN is set by the user so as not to cause an excessive cutting at the approach point AP, and such approach path input data DTAPIN is then corrected on the basis of the tool path data DTBM for not causing tool interference that has been prepared by using the segment height method.
  • An approach path data DTAP may be obtained such that, for a portion where a tool interference occurs in the approach region ARAP1, the tool may be moved on the basis of the tool path data DTBM which does not cause a tool interference, and at the same time an excessive cutting may be avoided at the approach point AP.
  • the workpiece 3 may be cut into the free curved surface contour SC specified as the process target contour while both an excessive cutting at the approach point AP and a tool interference at the approach region ARAP1 are avoided.
  • the present invention is not limited to this and it is possible to provide approach regions ARAP1 and ARAP2 on the both sides of cutting work region ARA so that machining can be effected from both sides.
  • the present invention is not limited to this and a predetermined approach path may be provided by a calculating process on the basis of the machining start direction APD at the approach point AP.
  • the present invention is not limited to this and it may also be calculated by various other methods such as the grid height method.
  • the present invention has been applied to the case of machining a mold, the present invention is not limited to this and may widely be applied to cases where products are directly machined.
  • the moving direction of the tool reaching the starting point of machining is determined such that it substantially coincide the tool's starting direction for machining whereby an approach path is provided through which an excessive cutting is avoided at the starting point of machining, and such approach path is corrected on the basis of a tool path that has been prepared correspondingly to the cutting target contour on the workpiece so that an approach path may be achieved through which, wile preventing a tool interference, an excessive cutting is avoided at the starting point of machining.

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  • Engineering & Computer Science (AREA)
  • Human Computer Interaction (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Mechanical Engineering (AREA)
  • Computing Systems (AREA)
  • Theoretical Computer Science (AREA)
  • Numerical Control (AREA)
EP9191121875A 1990-12-29 1991-12-19 Free curved surface producing method Withdrawn EP0493753A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP41625790A JP3209432B2 (ja) 1990-12-29 1990-12-29 物体形状切削方法
JP416257/90 1990-12-29

Publications (2)

Publication Number Publication Date
EP0493753A2 true EP0493753A2 (de) 1992-07-08
EP0493753A3 EP0493753A3 (en) 1994-10-05

Family

ID=18524489

Family Applications (1)

Application Number Title Priority Date Filing Date
EP9191121875A Withdrawn EP0493753A3 (en) 1990-12-29 1991-12-19 Free curved surface producing method

Country Status (3)

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EP (1) EP0493753A3 (de)
JP (1) JP3209432B2 (de)
KR (1) KR920011644A (de)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101630021B1 (ko) * 2013-12-10 2016-06-13 한국기계연구원 비구면 도광판 금형 가공방법
KR101767052B1 (ko) * 2015-06-17 2017-08-14 한국생산기술연구원 회전공구의 경로생성방법, 공구경로 생성장치, 공작기계 및 기록매체
KR101671840B1 (ko) * 2015-08-27 2016-11-04 한국생산기술연구원 회전공구의 경로생성방법, 공구경로 생성장치, 공작기계 및 기록매체

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3113970A1 (de) * 1981-04-07 1982-11-04 Dr. Johannes Heidenhain Gmbh, 8225 Traunreut Numerische bahnsteuerung fuer eine werkzeugmaschine
JPS62169210A (ja) * 1986-01-22 1987-07-25 Okuma Mach Works Ltd Ｎｃデ−タ作成装置における工具軌跡生成方式
DE3820566C2 (de) * 1987-06-19 1994-01-27 Mitsubishi Electric Corp Verfahren zum Ermitteln einer Bewegungsbahn eines Bearbeitungswerkzeugs einer von einer numerischen Steuervorrichtung gesteuerten Werkzeugmaschine
JPS63316212A (ja) * 1987-06-19 1988-12-23 Mitsubishi Electric Corp 数値制御装置

Also Published As

Publication number Publication date
JP3209432B2 (ja) 2001-09-17
JPH04242803A (ja) 1992-08-31
KR920011644A (ko) 1992-07-24
EP0493753A3 (en) 1994-10-05

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